Various types of lubricating oil filler openings and caps have in the past been provided for liquid containers such as, for example, those found in lubricating oil systems of internal combustion engines. Such filler devices have been provided in various locations such as on the ends of projecting tubes leading to the interior of an oil containing portion of an engine or directly on a wall of a lubricant containing chamber, such as the top of a valve cover.
Generally on automotive vehicle engines, the associated caps are made removable. However, various arrangements have been proposed in the past for utilizing caps attached by hinges or retained by other means which prevent their being removed from the engine and accidently misplaced during oil filling operations. Offsetting this advantage of hinged caps are various problems which may include higher cost, inadequate sealing and interference with the addition of lubricant. Moreover, since the cap and hinge structure are retained adjacent the filler opening when oil is being added, the possibility exists that oil will be spilled on the inner side of the cap and in the hinge area. This can cause a more difficult clean-up problem than if the cap were completely removed, leading, in some cases, to the presence of unsightly oil dripping and residue on the surface surrounding the oil filler and cap.